Potential utilisation of pulp and paper mill biosolids in composting and plant production: a case study at St. Marys Papers Ltd. (Canada)
The use of St Marys Paper biosolids as a soil additive or growth cover was investigated. Biosolids were mixed with a commercial potting media in five vol/vol ratios and employed in a greenhouse study. The biosolids were found to improve Pinus banksiana seedling growth, a 50% biosolids:50% ProMix mixture yielding the tallest plants and highest dry mass. To further biologically stabilise the biosolids, in–vessel composting studies were undertaken. Results indicated that a 3 parts biosolids:1 part wood chips:1 part sawdust mixture and initial C : N ratio of 30 sustained thermophilic conditions for 12 days reaching a maximum temperature of 52°C and final C : N ratio of 21.
Keywords: composting, biosolids, sludge, pulp and paper mills, metals, nutrients, carbon to nitrogen ratio, growth study, biostabilisation, Canada, potting media, seedling growth, waste management